понедельник, 22 июля 2019 г.

Squid Pro Glow As if escaping a shark, this squid shows off…


Squid Pro Glow


As if escaping a shark, this squid shows off its camouflage – playing with how light dances off its skin to ‘disappear’ in the eyes of predators. Its secret lies in light-changing organs beneath the skin – here chromatophores (yellow dots) are full of coloured pigments which can absorb certain colours of light. Recently researchers discovered that the same organs are also capable of structural colour – changing or diffracting the path of light rays. Along with other skin organs, the balance of these different talents helps to explain how squid skin shimmers to hide itself, or send signals to other squid. Bioengineers are hoping to mimic these natural designs as a human ‘smart skin’ – possibly as a form of camouflage for military defence or as wearable medical sensors to allow doctors to quickly assess at risk patients.


Written by John Ankers



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GSLV MkIII-M1 Successfully Launches Chandrayaan-2 spacecraft


ISRO — Chandrayaan-2 Mission logo.


July 22, 2019



GSLV carrying Chandrayaan-2 lift off

India’s Geosynchronous Satellite Launch Vehicle GSLV MkIII-M1, successfully launched the 3840 kg Chandrayaan-2 spacecraft into an earth orbit today (July 22, 2019). The spacecraft is now revolving round the earth with a perigee (nearest point to Earth) of 169.7 km and an apogee (farthest point to Earth) of 45,475 km.  Today’s flight marks the first operational flight of the GSLV Mk III.



Chandrayaan-2 launch

Video above: A GSLV Mk-III M1 launch vehicle launched the Chandrayaan-2 lunar mission from the Satish Dhawan Space Center at Sriharikota, India, on 22 July 2019, at 09:13 UTC (14:43 IST). The Chandrayaan-2 lunar mission aims to put the Vikram lander near South Pole of the Moon in September 2019. Subsequently, the Pragyan rover will roll out and carry out experiments on Lunar surface for a period of 1 Lunar day which is equal to 14 Earth days. Orbiter will continue its mission for a duration of one year. Video Credits: ISRO/SciNews.


After a smooth countdown lasting 20 hours, GSLV MkIII-M1 vehicle majestically lifted off from the Second Launch Pad at the Satish Dhawan Space Centre SHAR (SDSC SHAR), Sriharikota at the scheduled launch time of 1443Hrs (2:43 pm) Indian Standard Time (IST) with the ignition of its two S200 solid strap-on motors.  All the subsequent flight events occurred as scheduled.


About 16 minutes 14 seconds after lift-off, the vehicle injected Chandrayaan-2 spacecraft into an elliptical earth orbit. Immediately after spacecraft separation from the vehicle, the solar array of the spacecraft automatically got deployed and ISRO Telemetry, Tracking and Command Network (ISTRAC), Bengaluru successfully took control of the spacecraft.


ISRO Chairman Dr K Sivan congratulated the launch vehicle and satellite teams involved in this challenging mission. “Today is a historical day for Space Science and Technology in India. I am extremely happy to announce that GSLV MkIII-M1 successfully injected Chandrayaan-2 into an orbit of 6000 Km more than the intended orbit and is better.”


“Today is the beginning of the historical journey of India towards Moon and to land at a place near south pole to carry out scientific experiments to explore the unexplored. On July 15, 2019 ISRO intelligently observed a technical snag, Team ISRO worked out, fixed and corrected the snag within 24 hours. For the next one and a half day, the required tests were conducted to ensure that corrections made were proper and in right direction. Today ISRO bounced back with flying colours.” Dr. Sivan said.




Image above: Chandrayaan-2 («Lunar Trolley» in Hindi) will consist of an orbiter, an undercarriage and a rover, for a total weight of 3.8 tons.


In the coming days, a series of orbit manoeuvres will be carried out using Chandrayaan-2’s onboard propulsion system.  This will raise the spacecraft orbit in steps and then place it in the Lunar Transfer Trajectory to enable the spacecraft to travel to the vicinity of the Moon.


GSLV Mk III is a three-stage launch vehicle developed by ISRO. The vehicle has two solid strap-ons, a core liquid booster and a cryogenic upper stage. The vehicle is designed to carry 4 ton class of satellites into Geosynchronous Transfer Orbit (GTO) or about 10 tons to Low Earth Orbit (LEO).


Chandrayaan-2 is India’s second mission to the moon. It comprises a fully indigenous Orbiter, Lander (Vikram) and Rover (Pragyan). The Rover Pragyan is housed inside Vikram lander.


The mission objective of Chandrayaan-2 is to develop and demonstrate the key technologies for end-to-end lunar mission capability, including soft-landing and roving on the lunar surface. On the science front, this mission aims to further expand our knowledge about the Moon through a detailed study of its topography, mineralogy, surface chemical composition, thermo-physical characteristics and atmosphere leading to a better understanding of the origin and evolution of the Moon.



 ISRO’s graphic depiction of Chandrayaan 2 landing on the Moon

After leaving earth orbit and on entering Moon’s sphere of influence, the on-board propulsion system of Chandrayaan-2 will be fired to slow down the spacecraft. This will enable it to be captured into a preliminary orbit around the Moon. Later, through a set of manoeuvres, the orbit of Chandrayaan-2 around the moon will be circularised at 100 km height from the lunar surface.


Subsequently, the lander will separate from the Orbiter and enters into a 100 km X 30 km orbit around the Moon.  Then, it will perform a series of complex braking maneuvers to soft land in the South polar region of the Moon on September 7, 2019.


Following this, the Rover will roll out from the lander and carries out experiments on the lunar surface for a period of 1 lunar day, which is equal to 14 Earth days. The mission life of the lander is also 1 lunar day.The Orbiter will continue its mission for a duration of one year.


The orbiter had a lift-off weight of about 2,369 kg, while the lander and rover weighed 1,477 kg and 26 kg respectively.  The rover can travel up to 500 m (half a kilometre) and relies on electric power generated by its solar panel for functioning.



Chandrayaan-2 Lunar Orbiter

Chandrayaan-2 has several science payloads to facilitate a more detailed understanding of the origin and evolution of the Moon. The Orbiter carries eight payloads, the lander carries three, and the rover carries two.  Besides, a passive experiment is included on the lander.The Orbiter payloads will conduct remote-sensing observations from a 100 km orbit while the Lander and Rover payloads will perform in-situ measurements near the landing site.


The ground facilities constitute the third vital element of Chandrayaan-2mission.  They perform the important task of receiving the health information as well as the scientific data from the spacecraft. They also transmit the radio commands to the spacecraft. The Ground Segment of Chandrayaan-2 consists of Indian Deep Space Network, Spacecraft Control Centre and Indian Space Science Data Centre.


Today’s successful launch of Chandrayaan-2 is a significant milestone in this challenging mission.


Related articles:


India revives lunar mission Monday
https://orbiterchspacenews.blogspot.com/2019/07/india-revives-lunar-mission-monday.html


Moon mission for an Indian probe
https://orbiterchspacenews.blogspot.com/2019/07/moon-mission-for-indian-probe.html


For more information about ISRO and Chandrayaan-2 mission, visit:


Indian Space Research Organisation (ISRO): https://www.isro.gov.in/


Chandrayaan-2 mission: https://www.isro.gov.in/chandrayaan2-home-0


Images, Video (mentioned), Text, Credits: ISRO.


Greetings, Orbiter.chArchive link


Spawn of the triffid? Tiny organisms give us glimpse into complex evolutionary tale

Two newly discovered organisms point to the existence of an ancient organism that resembled a tiny version of the lumbering, human-eating science fiction plants known as ‘triffids,’ according to research in the journal Nature.











Spawn of the triffid? Tiny organisms give us glimpse into complex evolutionary tale
Rhodelphis limneticus: You can see the tiny flagella that allow this protist to move and hunt
[Credit: Denis Tikhonenkov]

The microscopic protists Rhodelphis limneticus and Rhodelphis marinus are genetically ‘sisters’ to red algae, but couldn’t be more different. Red algae are fleshy, large organisms with a simple genome that perform photosynthesis, just like plants. Rhodelphis are single-cell predators with a large, complex genome.
The two protists have a chloroplast, though it is not photosynthetic anymore, pointing to their close ties with plants in the distant past. They also have flagella, a whip-like structure which allows them to move and hunt for their dinner.


«Rhodelphis shows that there was a period of time when the ancestors of plants and algae probably absorbed sunlight to generate energy, while also swimming around eating things,» says University of British Columbia (UBC) biologist Patrick Keeling, the senior researcher leading the study.











Spawn of the triffid? Tiny organisms give us glimpse into complex evolutionary tale
Callophyllis: A type of red algae [Credit: Patrick Keeling Lab]

If we think of life as a big family, with algae and Rhodelphis as sisters, their ancient mother was more like a triffid than your standard plant. Triffids are the tall, mobile, carnivorous plants featured in John Wyndham’s 1951 novel The Day of the Triffids.
This surprising evolutionary twist emphasizes the need for robust sampling in order to reconstruct a more complete picture of life.


«Most people don’t look twice at organisms like this under a microscope, and getting them into culture may be hard work but it’s the only way to really see the true diversity of life,» says Denis Tikhonenkov, the microbiologist who first captured the tiny predators and splits his time between UBC and the Russian Academy of Science.











Spawn of the triffid? Tiny organisms give us glimpse into complex evolutionary tale
Chondracanthus exasperatus or Turkish Towel. A species of red algae
[Credit: Patrick Keeling]

«There are gems in nature we haven’t found, and sadly the importance of ‘old-fashioned’ exploration is being forgotten,» Keeling says. «These new lineages are a great example — making us realize we were previously seeing things backwards and now we recognize plants had ancestors we couldn’t have imagined.»


Keeling and Tikhonenkov worked on the project with the outstanding Russian Academy of Sciences protistologist Alexander Mylnikov, who died after a long illness shortly before the paper came to press.


Source: University of British Columbia [July 17, 2019]



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Plant viruses may be reshaping our world

The community of viruses is staggeringly vast. Occupying every conceivable biological niche, from searing undersea vents to frigid tundra, these enigmatic invaders, hovering between inert matter and life, circumnavigate the globe in the hundreds of trillions. They are the most abundant life forms on earth.











Plant viruses may be reshaping our world
Mysteries abound in the viral world. Scientists still aren’t quite sure where they came from.
The illustration describes three leading theories. According to the virus-first hypothesis,
RNA molecules capable of enzymatic activity and self-replication preceded cellular forms
at the dawn of life. According to the reduction hypothesis, viruses came from small primordial
cells that lost their cellular elements in the course of evolution, while retaining their genetic
material and the machinery required for replication. According to the escape hypothesis, viruses
 arose from cellular RNA or/and DNA fragments such as plasmids and transpozons. During
cell fission, a smaller cell-like entity may have formed, engulfing a self replicating RNA
fragment and a coat encoding RNA segment, forming a virus
[Credit: Shireen Dooling]

Viruses are justly feared as ingenious pathogens, causing diseases in everything they invade, including virtually all bacteria, fungi, plants and animals. Recent advances in the field of virology, however, suggest that viruses play a more significant and complex role than previously appreciated, and may be essential to the functioning of diverse ecosystems.


We now know that humans contain roughly 100,000 pieces of viral DNA elements, which make up around 8 percent of our genome. Speculation on the role of these ancient viral fragments ranges from protection against disease to increasing the risk of cancer or other serious illnesses, though researchers acknowledge they have barely scratched the surface of this enigma.


A new review article appearing in the journal Nature Reviews Microbiology highlights the evolution and ecology of plant viruses. Arvind Varsani, a researcher at ASU’s Biodesign Institute joins an international team to explore many details of viral dynamics. They describe the subtle interplay between three components of the viral infection process, the virus itself, the plant cell hosts infected by the virus and the vectors that act as go-betweens—an intricate system evolving over some 450 million years. All three elements are embedded within wider relations of the surrounding ecosystem.


Recent studies in the field of virology have shown that viruses are sometimes beneficial to the organisms they infect. «Prior to this people have always seen viruses as disease-causing entities,» Varsani says. «This breaks all the dogmas of how we study viruses. We have a section where we review mutualism and symbiosis and also how some of the symbiotic relationships are being uncoupled.»


Elusive wanderer


In 1892, Dmitry Ivanovsky, a Russian botanist, conducted a simple experiment that would have momentous implications for science and medicine. He collected sap from a diseased tobacco plant, fed the substance through very fine pores and showed that this filtered fluid could infect a healthy tobacco plant. The filtering ensured that whatever the disease-causing entity was, it was tinier than a bacterium.


A Dutch plant specialist and microbiologist Martinus Beijerinck dubbed the mysterious pathogenic substance a virus, though its true form—invisible to light microscopy— only appeared in 1931, with the invention of the electron microscope. A rod-shaped plant invader, known as tobacco mosaic virus, had revealed itself—the first virus on record. Since this time, thousands of distinct species have been identified, yet they represent a tiny fraction of the viral universe, most of which remains unexplored.


Indeed, even the question of what constitutes a virus has no single answer. Their sizes vary enormously, from a virus like Ebola, carrying a tiny handful of genes, to recently discovered giant viruses. Rivalling some bacteria in size, giant viruses can carry elements of the machinery required for translation, throwing their status as non-living entities into question.


«The way I look at viruses now is from a philosophical angle,» Varsani says. «They are a dynamic entity and they have multiple lifestyles, ranging from basic, where the virus is fully reliant on the host for replication, to some cases where it’s only partly reliant on the host.» Because some viruses can evolve so rapidly, trading and acquiring new genetic elements, their genomes can become chimeric or even fragmented, making their proper classification a serious challenge for the field of virology.


From the standpoint of ecology, plant viruses are particularly important for a number of reasons. Plants make up over 80 percent of the biomass on earth, exerting a greater impact on the planet’s diverse ecosystems than viruses infecting other kingdoms of life. Plant viruses have obvious importance for food crops and ornamental plants, and a range of viruses are responsible for an estimated $60 billion in crop losses worldwide each year.


To capture the astonishing richness of the planet’s viral universe, researchers have gone beyond early methods of pinpointing individual virus particles and analyzing them. Techniques of metaviromics are used to probe environments for the full panoply of viruses they contain. The method, which relies on piecing together multiple DNA or RNA genomes from environmental samples, has been recently used to identify vast numbers of previously undocumented viruses. In the case of plant viruses, these viral fragments are often extracted from the insect vectors that ferry the viruses from plant to plant.


New methods uncover a welter of new viruses


Metaviromic sequencing is a particularly powerful technique for investigating viral communities. Unlike cellular life, which has a single, common origin, viruses are polyphyletic, meaning that they are the result of multiple origins. No single gene has been identified that is shared by all viruses. While common protein motifs have been observed in viral capsids, these are likely the result of convergent evolution or horizontal gene transfer, rather than inherited elements.











Plant viruses may be reshaping our world
The viral world constitutes the most abundant life form on earth. The graphic illustrates the staggering
amount of genetic material contained in viruses [Credit: Shireen Dooling]

The strategy of metaviromics is particularly useful for teasing out mutualistic relationships between plants, vectors and viruses and their changing relationships over time. As so much research since the inception of virology has been focused on viruses as disease-causing agents in humans and plants, the nature and degree of mutualistic interactions between viruses, vectors and hosts is most likely underrepresented.


The authors speculate that viruses may play an important role in maintaining biodiversity and helping plants adapt to their environment by limiting the growth of genetically homogeneous plants, including crops. New studies of viral ecology seek to understand the extent and importance of both pathogenic and mutualistic interactions. An all-important link in the chain of infection is the behavior of particular insect vectors and their modes of viral transmission, though numerous other factors come into play, including nutrients, water resources, heat and cold stress, and adverse soil conditions.


Viral intermediaries


Vectors play an outsized role in the world of plant viruses. Unlike animal viruses, plant viruses are not usually transmitted through direct contact between infected and uninfected individuals. Instead, plant viruses disseminate through vectors, (especially insects) as well as through pollen and seeds.


It is believed that the mode of viral transmission plays a role in the virus’ effect on its host. If the virus is transmitted via seeds or pollen, the virus should limit its harmful effect on the reproductive success of the host plant, perhaps even conveying an adaptive advantage over uninfected plants.


The viral passage from parent to daughter plant is known as vertical transmission. By contrast, horizontal viral transmission occurs when insect vectors transit the virus from plant to plant. Such vector-borne assaults can be more merciless to the infected plant and only need ensure their continued spread to a suitable number of healthy plants for the virus to be successful.


Many kinds of vectors can transmit plant viruses, including arachnids, fungi, nematodes, and some protists, though more than 70 percent of known plant viruses are transmitted by insects, most from the biological order Hemiptera, which includes cicadas, aphids, planthoppers, leafhoppers and shield bugs.


Insects of this kind can make use of mouthparts constructed for piercing and extracting sap or plant cell material. Insect transmission of plant viruses can occur through excretion of virus particles in saliva following feeding on an infected plant. Alternately, the plant virus can become permanently incorporated into the insect’s salivary glands, allowing the vector to transmit the virus to new plants throughout the insect’s lifetime.


Intriguingly, a number of insect-transmitted plant viruses may have evolved mechanisms to influence vector behavior, making infected plants more attractive to sap-feeding insects or ensuring that infected plants produce chemicals that promote insect behaviors that help facilitate transmission.


In addition to their complex and varied chains of infection, some plant viruses have another unique property. Such viruses transmit their genomes in multiple packets, each containing only part of the virus’ complete genetic code, encapsulated in a separate virus particle. This peculiar strategy, which requires the co-transmission of several viral particles to a new host in order to ensure the integrity of the viral genome, is a feature believed to be unique to plant viruses. The nature and evolution of these so-called multipartite viruses remains a biological puzzle.


Plant viruses display considerable ingenuity in their strategies, which are highly dependent on their given environment. Some are generalists, invading multiple species, while other viruses are specialists that favour a narrow range of plant hosts. This selectivity may develop with time, through a process known as adaptive radiation. This typically occurs when a virus faces a heterogeneous habitat and becomes adaptively specialized to exploit particular ecological resources while becoming maladapted to exploit others. Such specialization acts to limit competition between different viral lineages or species. Alternatively, generalist viruses infect multiple plant hosts but must compete for these resources with other viruses. This situation tends to result in a viral population of low diversity dominated by the most acutely adapted viral genotypes.


The arrival of viruses


While researchers agree that viruses lack a single common ancestor, a detailed picture of how (and when) they emerged in the web of life remains deeply contested. Three common hypotheses compete for dominance as an explanatory framework, though they are not mutually exclusive. Perhaps viruses evolved from free-living cells, as the devolution or regressive hypothesis states. They could also have originated from RNA and DNA molecules that somehow escaped from living cells. Alternatively, viruses may have once existed as self-replicating entities that evolved alongside cells, eventually losing their independent status.


Ongoing metaviromic research of viral diversity is helping to uncover foundational relationships among viruses and pinpoint common origins among many plant, fungal and arthropod viruses. Of particular concern for the future are the ways in which human-caused disruptions to ecosystems across the planet, which are occurring at rates unprecedented in earth’s history, are reforming virus, vector and host relationships.


The effects of these disruptions may be to foster emergent viruses with heightened abilities to cause disease in their hosts. As ecological communities become more tightly interwoven through changes in human land use, existing interaction networks that have acted over evolutionary time to stabilize host relations with native vectors and viruses can suddenly shift. Any lethal entity entering this kind of disrupted ecosystem is much likelier to rapidly spread through the population and aggressively sweep through different organisms. The future health and sustainability of both human and plant populations will benefit from an improved understanding of the many subtle interrelationships governing the most ubiquitous viruses—those colonizing plants.


Author: Richard Harth | Source: Arizona State University [July 17, 2019]



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Manmade ruin adds 7,000 species to endangered ‘Red List’

Mankind’s destruction of nature is driving species to the brink of extinction at an «unprecedented» rate, the leading wildlife conservation body warned Thursday as it added more than 7,000 animals, fish and plants to its endangered «Red List».











Manmade ruin adds 7,000 species to endangered 'Red List'
The Roloway Monkey of Cote d’Ivoire and Ghana has fewer than 2,000 left in the wild
[Credit: Sebastien Bozon/AFP]

From the canopies of tropical forests to the ocean floor, the International Union for the Conservation of Nature (IUCN) said iconic species of primates, rays, fish and trees were now classified as critically endangered.


The group has now assessed more than 105,000 species worldwide, around 28,000 of which risk extinction.


While each group of organisms face specific threats, human behaviour, including overfishing and deforestation, was the biggest driver of plummeting populations.


«Nature is declining at rates unprecedented in human history,» said IUCN acting director general, Grethel Aguilar. «We must wake up to the fact that conserving nature’s diversity is in our interest.»


In May the United Nations released its generational assessment of the state of the environment. It made for grim reading.


The report warned that as many as one million species were now at risk of extinction, many within decades, as human consumption of freshwater, fossil fuels and other natural resources skyrockets.


It found that more than 90 percent of marine fish stocks are now either overfished or fished to the limit of sustainability.


The IUCN singled out a number of sea and freshwater fish that now occupy its highest threat category of «critically endangered»—the next step on the Red List is extinction.


Wedgefishes and giant guitarfishes, known collectively as Rhino Rays due to their elongated snouts, are now the most imperilled marine families on Earth.


The False Shark Ray is on the brink of extinction after overfishing in the waters off of Mauritania saw its population collapse 80 percent in the last 45 years.


Seven species of primate are closer to extinction on the new list, including the Roloway Monkey of Cote d’Ivoire and Ghana, with fewer than 2,000 individuals left in the wild.


Prime culprits are humans hunting the animals for bushmeat and «severe habitat loss» as forest is converted to land to grow food.


40 percent of all primates in West and Central Africa are now threatened with extinction, according to the IUCN.


«Species targeted by humans for food tend to become endangered much more quickly,» Craig Hilton-Taylor, head of the IUCN Red List Unit, told AFP.


«Species in environments with lots of deforestation for agriculture end up being impacted.»


The updated list shows that over half of Japan’s freshwater fish and more than a third of Mexico’s are threatened with extinction due to the loss of free-flowing rivers and increasing pollution.


More than 500 deep-sea bony fish and molluscs have been added to the list for the first time posing something of a conservation conundrum as the space they inhabit—1,000 metres (3,280 feet) beneath the surface—is often beyond national boundaries.


«The alarm bell has been sounding again and again concerning the unravelling crisis in freshwater and marine wildlife,» said Andrew Terry, director of conservation and policy at the Zoological Society of London.


«Many of these ancient marine species have been around since the age of the dinosaurs and losing just one of these species would represent a loss of millions of years of evolutionary history.»


Author: Patrick Galey | Source: AFP [July 18, 2019]



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How mammals’ brains evolved to distinguish odors is nothing to sniff at

The world is filled with millions upon millions of distinct smells, but how mammals’ brains evolved to tell them apart is something of a mystery.











How mammals' brains evolved to distinguish odors is nothing to sniff at
A section of the front part of the piriform cortex, an area of the brain involved in the sense of smell. The cortex layers
are stained with florescent antibodies to better distinguish key differences. Layer 1 contains two separate sections;
the layer closest to the black-colored surface (1a) is stained bright green, while the second part (1b) is stained orange.
Layer 2 is stained white and contains a high density of neurons. Olfactory bulb neurons, important in smell processing,
send signals to the branches of neurons in layer 1a. These neurons have cell bodies located in layer 2.
Layer 2 neurons communicate with one another in layer 1b [Credit: Salk Institute]

Now, two neuroscientists from the Salk Institute and UC San Diego have discovered that at least six types of mammals—from mice to cats—distinguish odors in roughly the same way, using circuitry in the brain that’s evolutionarily preserved across species.


«The study yields insights into organizational principles underpinning brain circuitry for olfaction in mammals that may be applied to other parts of the brain and other species,» says Charles Stevens, distinguished professor emeritus in Salk’s Neurobiology Laboratory and coauthor of the research published in Current Biology.


In brief, the study reveals that the size of each of the three components of the neural network for olfaction scales about the same for each species, starting with receptors in the nose that transmit signals to a cluster of neurons in the front of the brain called the olfactory bulb which, in turn, relays the signals to a «higher functioning» region for odor identification called the piriform cortex.


«These three stages scale with each other, with the relationship of the number of neurons in each stage the same across species,» says Shyam Srinivasan, assistant project scientist with UC San Diego’s Kavli Institute for Brain and Mind, and the paper’s coauthor. «So, if you told me the number of neurons in the nose, I could predict the number in the piriform cortex or the bulb.»


The current study builds on research by the same duo, published in 2018, which described how mouse brains process and distinguish odors using what’s known as «distributed circuits.» Unlike the visual system, for example, where information is transmitted in an orderly manner to specific parts of the visual cortex, the researchers discovered that the olfactory system in mice relies on a combination of connections distributed across the piriform cortex.


Following that paper, Stevens and Srinivasan sought to determine if the distributed neural circuitry revealed in mice is similar in other mammals. For the current work, the researchers analyzed mammal brains of varying sizes and types. Their calculations, plus previous studies over the past few years, were used to estimate brain volumes. Stevens and Srinivasan used a variety of microscopy techniques that let them visualize different types of neurons that form synapses (connections) in the olfactory circuitry.


«We couldn’t count every neuron, so we did a survey,» says Srinivasan. «The idea is that you take samples from different represented areas, so any irregularities are caught.»


The new study revealed that the average number of synapses connecting each functional unit of the olfactory bulb (a glomerulus) to neurons in the piriform cortex is invariant across species.


«It was remarkable to see how these were conserved,» says Stevens.


Specifically, identification of individual odors is linked to the strength and combination of firing neurons in the circuit that can be likened to music from a piano whose notes spring from the depression of multiple keys to create chords, or the arrangement of letters that form the words on this page.


«The discrimination of odors is based on the firing rate, the electric pulse that travels down the neuron’s axon,» says Srinivasan. «One odor, say for coffee, may elicit a slow response in a neuron while the same neuron may respond to chocolate at a faster rate.»


This code used for olfaction is different than other parts of the brain.


«We showed that the connectivity parameters and the relationship between different stages of the olfactory circuit are conserved across mammals, suggesting that evolution has used the same design for the circuit across species, but just changed the size to fit the animals’ environmental niche,» says Stevens.


In the future, Stevens plans to examine other regions of the brain in search of other distributed circuits whose function is based on similar coding found in this study.


Srinivasan says he will focus on how noise or variability in odor coding determines the balance between discrimination and learning, explaining that the variability the duo is finding in their work might be a mechanism for distinguishing odors, which could be applied to making better machine learning or AI systems.


Author: Salk Institute [July 18, 2019]



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Scientists discover how and when a subterranean ocean emerged

«The mechanism which caused the crust that had been altered by seawater to sink into the mantle functioned over 3.3 billion years ago. This means that a global cycle of matter, which underpins modern plate tectonics, was established within the first billion of the Earth’s existence, and the excess water in the transition zone of the mantle came from the ancient ocean on the planet’s surface,» said project leader and co-author of the article Alexander Sobolev, a member of the Russian Academy of Sciences (RAS) and Doctor of Geological and Mineralogical Sciences who is a Professor at Vernadsky Institute for Geochemistry and Analytical Chemistry under the Russian Academy of Sciences.











Scientists discover how and when a subterranean ocean emerged
View of the Komati River in Barberton Mountain Land (South Africa)
[Credit: Alexander Sobolev]

The Earth’s crust consists of large continuously moving blocks known as tectonic plates. Mountains are produced when these plates collide and rise up, and the shock of the collisions leads to earthquakes and tsunamis. These plates move very actively under the World Ocean: old oceanic crust, including the minerals that have absorbed seawater, sinks deep into the Earth’s mantle. Some of this water is released again due to the effect of high temperatures and plays a role in volcanic eruptions, such as those that occur in Kamchatka, the Kuril islands and Japan.


The water that remains in minerals of the oceanic crust at higher temperatures continues to descend into the deep mantle and accumulates at a depth of 410-660 km in the structure of the minerals wadsleyite and ringwoodite and high-pressure modifications of olivine (magnesium iron silicate), the main mineral of the mantle. Experiments have shown that these minerals can contain significant quantities of water and chlorine. This is how the greatest part of the World Ocean could be «pumped» into the planet’s interior over the billions of years of its existence. This process is only a part of the global cycle of the Earth’s matter, which is called convection and underpins plate tectonics, a feature that distinguishes our planet from all other bodies in the Solar System. Many scientists study this mechanism, trying to understand at which stage of the Earth’s history it appeared.


In order to study the mantle of our planet and investigate its composition, geochemists (scientists who specialise in the chemical composition of the Earth and the processes of rock formation) use samples of volcanic rocks that consist of solidified magma of the mantle. This is a silicate melt enriched in volatile components, such as water, carbon dioxide, chlorine and sulphur. There are different types of magma: scientists commonly use basaltic lava (with a temperature of approximately 1200°C), but komatiitic magma, which was erupted during the early history of the Earth, is hotter (at 1500-1600°C). It can help to describe the evolution of the Earth’s inner layers, as it matches the composition of the mantle more completely.


Komatiites are a type of volcanic rock that formed from komatiitic magma billions of years ago and whose composition has changed dramatically in the intervening epochs. It no longer provides information about the content of volatile components, such as water and chlorine. But these rocks still contain remnants of the magmatic mineral olivine, which trapped inclusions of solidified magma during the crystallisation process and protected them from subsequent changes.











Scientists discover how and when a subterranean ocean emerged
Schematic diagram of water and chlorine transfer by the oceanic crust into the transitional zone of the
 mantle and the subsequent capture of the resulting material by an Archaean mantle plume
[Credit: Evgeny Asafov]

Such inclusions, just tens of microns across, retained detailed information about the composition of komatiitic melts, including the content of water and chlorine and the isotopic composition of hydrogen. In order to extract this information, inclusions of solidified magma must be heated to the natural melting point of over 1500°C and then immediately tempered to produce clear tempered glass that can later be used for chemical analyses.


In 2016, an international group headed by scientists from the Vernadsky Institute for Geochemistry and Analytical Chemistry studied komatiitic magma of the Abitibi greenstone belt in Canada, which is 2.7 billion years old. Greenstone belts are territories consisting of magmatic rocks that contain greenish minerals. This was the first article that the team published in Nature as part of the project supported by the Russian Science Foundation grant.


At that time, the scientists collected initial data on the content of water and a variety of labile elements, such as chlorine, lead and barium, in the transition zone between the upper and lower mantle layers at a depth of 410-660 km, which led them to hypothesise that an ancient subterranean water reservoir once existed that was comparable in mass to the present-day World Ocean. The scientists believe that such a quantity of water was accumulated at the early stages of the Earth’s development.


«In the new article, we presented geochemical data indicating that the cycle of global immersion of oceanic crust into the mantle began much earlier than most experts believed, and it could have functioned as early as the first billion years of the Earth’s history,» noted Alexander Sobolev.


In the course of the work, the scientists once again investigated the composition of komatiite magma, but of a different origin: it was collected from the Barberton greenstone belt in South Africa, which is 3.3 billion years old. The magma was heated using a specialised high-temperature apparatus that can withstand temperatures of up to 1700°C. The geochemists found out that the previously discovered deep water-containing reservoir was already present in the Earth’s mantle in the Palaeoarchaean era, 600 million years earlier than established in the previous study.


Source: AKSON Russian Science Communication Association [July 18, 2019]



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Jurassic fossil shows how early mammals could swallow like their modern descendants

The 165-million-year-old fossil of Microdocodon gracilis, a tiny, shrew-like animal, shows the earliest example of modern hyoid bones in mammal evolution.











Jurassic fossil shows how early mammals could swallow like their modern descendants
Life reconstructions of Microdocodon gracilis — a docodont mammaliaform. Microdocodon was a tiny animal.
It has a skull length of 2 cm (3/4 inch), a head-body length about 6 cm (2 inches), and a long tail about 8 cm
(about 3 inches) in length. The animal likely weighed between 5 grams to 9 gram (less than 1/3 of an ounce).
Its slender and gracile skeletal elements suggest that it was an agile and active animal living on the tree.
 Its teeth were for insectivorous diet. This reconstruction depicts Microdocodon as a nocturnal animal
 active on a bennettitalean tree of the Jurassic [Credit: April I. Neander]

The hyoid bones link the back of the mouth, or pharynx, to the openings of the esophagus and the larynx. The hyoids of modern mammals, including humans, are arranged in a «U» shape, similar to the saddle seat of children’s swing, suspended by jointed segments from the skull. It helps us transport and swallow chewed food and liquid — a crucial function on which our livelihood depends.


Mammals as a whole are far more sophisticated than other living vertebrates in chewing up food and swallowing it one small lump at a time, instead of gulping down huge bites or whole prey like an alligator.


«Mammals have become so diverse today through the evolution of diverse ways to chew their food, weather it is insects, worms, meat, or plants. But no matter how differently mammals can chew, they all have to swallow in the same way,» said Zhe-Xi Luo, PhD, a professor of organismal biology and anatomy at the University of Chicago and the senior author of a new study of the fossil, published this week in the journal Science.


«Essentially, the specialized way for mammals to chew and then swallow is all made possible by the agile hyoid bones at the back of the throat,» Luo said.











Jurassic fossil shows how early mammals could swallow like their modern descendants
The fossil of Microdocodon gracilis is preserved in two rock slabs, and consists of a main part (PMOL-AM00025A, left)
and a counter part (PMOL-AM00025B, right). It was found in a site near the Wuhua village in the Daohugou area
of Inner Mongolia, China, and the estimated age of the fossil site is at least 164 million years. The type specimen
of this new mammaliaform is deposited in the Paleontological Museum of Liaoning (Shenyang, China)
[Credit: Zhe-Xi Luo]

This modern hyoid apparatus is mobile and allows the throat muscles to control the intricate functions to transport and swallow chewed food or drink fluids. Other vertebrates also have hyoid bones, but their hyoids are simple and rod-like, without mobile joints between segments. They can only swallow food whole or in large chunks.


When and how this unique hyoid structure first appeared in mammals, however, has long been in question among paleontologists. In 2014, Chang-Fu Zhou, PhD, from the Paleontological Museum of Liaoning in China, the lead author of the new study, found a new fossil of Microdocodon preserved with delicate hyoid bones in the famous Jurassic Daohugou site of northeastern China. Soon afterwards, Luo and Thomas Martin from the University of Bonn, Germany, met up with Zhou in China to study the fossil.


«It is a pristine, beautiful fossil. I was amazed by the exquisite preservation of this tiny fossil at the first sight. We got a sense that it was unusual, but we were puzzled about what was unusual about it,» Luo said. «After taking detailed photographs and examining the fossil under a microscope, it dawned on us that this Jurassic animal has tiny hyoid bones much like those of modern mammals.»


This new insight gave Luo and his colleagues added context on how to study the new fossil. Microdocodon is a docodont, from an extinct lineage of near relatives of mammals from the Mesozoic Era called mammaliaforms. Previously, paleontologists anticipated that hyoids like this had to be there in all of these early mammals, but it was difficult to identify the delicate bones. After finding them in Microdocodon, Luo and his collaborators have since found similar fossilized hyoid structures in other Mesozoic mammals.











Jurassic fossil shows how early mammals could swallow like their modern descendants
Modern mammals, such as the dog and the platypus, have segmented hyoid bones with mobile joints, arranged in
saddle-like configuration. The new fossil of Microdocodon shows that its hyoids have the jointed segments,
and arranged in a saddle shape, as those of modern mammals [Credit: April Neander]

«Now we are able for the first time to address how the crucial function for swallowing evolved among early mammals from the fossil record,» Luo said. «The tiny hyoids of Microdocodon are a big milestone for interpreting the evolution of mammalian feeding function.»


Luo also worked with postdoctoral scholar Bhart-Anjan Bhullar, PhD, now on the faculty at Yale University, and April Neander, a scientific artist and expert on CT visualization of fossils at UChicago, to study casts of Microdocodon and reconstruct how it lived.


The jaw and middle ear of modern mammals are developed from (or around) the first pharyngeal arch, structures in a vertebrate embryo that develop into other recognizable bones and tissues. Meanwhile, the hyoids are developed separately from the second and the third pharyngeal arches. Microdocodon has a primitive middle ear still attached to the jaw like that of other early mammals like cynodonts, which is unlike the ear of modern mammals. Yet its hyoids are already like those of modern mammals.


«Hyoids and ear bones are all derivatives of the primordial vertebrate mouth and gill skeleton, with which our earliest fishlike ancestors fed and respired,» Bhullar said. «The jointed, mobile hyoid of Microdocodon coexists with an archaic middle ear — still attached to the lower jaw. Therefore, the building of the modern mammal entailed serial repurposing of a truly ancient system.»


The tiny, shrew-like creature likely weighed only 5 to 9 grams, with a slender body, and an exceptionally long tail. The dimensions of its limb bones match up with those of modern tree-dwellers.


«Its limb bones are as thin as matchsticks, and yet this tiny Mesozoic mammal still lived an active life in trees,» Neander said.


The fossil beds that yielded Microdocodon are dated 164 to 166 million years old. Microdocodon co-existed with other docodonts like the semiaquatic Castorocauda, the subterranean Docofossor, the tree-dwelling Agilodocodon, as well as some mammaliaform gliders.


Author: Matt Wood | Source: University of Chicago Medical Center [July 18, 2019]



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2019 July 22 HDR: Earth’s Circular Shadow on the Moon…


2019 July 22


HDR: Earth’s Circular Shadow on the Moon
Image Credit & Copyright: Cristian Fattinnanzi


Explanation: What could create such a large circular shadow on the Moon? The Earth. Last week’s full Moon – the Buck Moon – was so full that it fell almost exactly in a line with the Sun and the Earth. When that happens the Earth casts its shadow onto the Moon. The circularity of the Earth’s shadow on the Moon was commented on by Aristotle and so has been noticed since at least the 4th century BC. What’s new is humanity’s ability to record this shadow with such high dynamic range (HDR). The featured HDR composite of last week’s partial lunar eclipse combines 15 images and include an exposure as short as 1/400th of a second – so as not to overexpose the brightest part – and an exposure that lasted five seconds – to bring up the dimmest part. This dimmest part – inside Earth’s umbra – is not completely dark because some light is refracted through the Earth’s atmosphere onto the Moon. A total lunar eclipse will occur next in 2021 May.


∞ Source: apod.nasa.gov/apod/ap190722.html


‘An Economy Of Stones’ Poetry Reading and Interactive Exhibition at Ebor...











‘An Economy Of Stones’ Poetry Reading and Interactive Exhibition at Ebor Studios and Gallery Frank, Littleborough, 20.7.19.


Thanks to everyone who made it a special evening!


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We Worked on Apollo

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On July 20, 1969, the world watched as Apollo 11 astronauts Neil Armstrong and Buzz Aldrin took their first steps on the Moon. It was a historic moment for the United States and for humanity. Until then, no human had ever walked on another world. To achieve this remarkable feat, we recruited the best and brightest scientists, engineers and mathematicians across the country. At the peak of our Apollo program, an estimated 400,000 Americans of diverse race and ethnicity worked to realize President John F. Kennedy’s vision of landing humans on the Moon and bringing them safely back to Earth. The men and women of our Ames Research Center in California’s Silicon Valley supported the Apollo program in numerous ways – from devising the shape of the Apollo space capsule to performing tests on its thermal protection system and study of the Moon rocks and soils collected by the astronauts. In celebration of the upcoming 50th anniversary of the Apollo 11 Moon landing, here are portraits of some of the people who worked at Ames in the 1960s to help make the Apollo program a success.


“I knew Neil Armstrong. I had a young daughter and she took her first step on the day that Neil stepped foot on the Moon. Isn’t that something?”


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Hank Cole did research on the design of the Saturn V rocket, which propelled humans to the Moon. An engineer, his work at Ames often took him to Edwards Air Force Base in Southern California, where he met Neil Armstrong and other pilots who tested experimental aircraft.


“I worked in a lab analyzing Apollo 11 lunar dust samples for microbes. We wore protective clothing from head to toe, taking extreme care not to contaminate the samples.”


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Caye Johnson came to Ames in 1964. A biologist, she analyzed samples taken by Apollo astronauts from the Moon for signs of life. Although no life was found in these samples, the methodology paved the way for later work in astrobiology and the search for life on Mars.


“I investigated a system that could be used to provide guidance and control of the Saturn V rocket in the event of a failure during launch. It was very exciting and challenging work.”


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Richard Kurkowski started work at Ames in 1955, when the center was still part of the National Advisory Committee on Aeronautics, NASA’s predecessor. An engineer, he performed wind tunnel tests on aircraft prior to his work on the Apollo program.


“I was 24 and doing some of the first computer programming work on the Apollo heat shield.  When we landed on the Moon it was just surreal. I was very proud. I was in awe.”


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Mike Green started at Ames in 1965 as a computer programmer. He supported aerospace engineers working on the development of the thermal protection system for the Apollo command module. The programs were executed on some of earliest large-scale computers available at that time.


“In 1963 there was alarm that the Apollo heat shield would not be able to protect the astronauts. We checked and found it would work as designed. Sure enough, the astronauts made it home safely!”


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Gerhard Hahne played an important role in certifying that the Apollo spacecraft heat shield used to bring our astronauts home from the Moon would not fail. The Apollo command module was the first crewed spacecraft designed to enter the atmosphere of Earth at lunar-return velocity – approximately 24,000 mph, or more than 30 times faster than the speed of sound.


“I was struck by the beauty of the photo of Earth rising above the stark desert of the lunar surface. It made me realize how frail our planet is in the vastness of space.”


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Jim Arnold arrived at Ames in 1962 and was hired to work on studying the aerothermodynamics of the Apollo spacecraft. He was amazed by the image captured by Apollo 8 astronaut Bill Anders from lunar orbit on Christmas Eve in 1968 of Earth rising from beneath the Moon’s horizon. The stunning picture would later become known as the iconic Earthrise photo.


“When the spacecraft returned to Earth safely and intact everyone was overjoyed. But I knew it wasn’t going to fail.”


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Howard Goldstein came to Ames in 1967. An engineer, he tested materials used for the Apollo capsule heat shield, which protected the three-man crew against the blistering heat of reentry into Earth’s atmosphere on the return trip from the Moon. 


“I was in Houston waiting to study the first lunar samples. It was very exciting to be there when the astronauts walked from the mobile quarantine facility into the building.”


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Richard Johnson developed a simple instrument to analyze the total organic carbon content of the soil samples collected by Apollo astronauts from the Moon’s surface. He and his wife Caye Johnson, who is also a scientist, were at our Lunar Receiving Laboratory in Houston when the Apollo 11 astronauts returned to Earth so they could examine the samples immediately upon their arrival.


“I tested extreme atmospheric entries for the Apollo heat shield. Teamwork and dedication produced success.”


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William Borucki joined Ames in 1962. He collected data on the radiation environment of the Apollo heat shield in a facility used to simulate the reentry of the Apollo spacecraft into Earth’s atmosphere.  


Join us in celebrating the 50th anniversary of the Apollo 11 Moon landing and hear about our future plans to go forward to the Moon and on to Mars by tuning in to a special two-hour live NASA Television broadcast at 1 pm ET on July 19. Watch the program at www.nasa.gov/live.


Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.


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